Valve-gear for steam-engines



(No Model.)

- A. J. STEVENS.

VALVE GEAR EOE STEAM ENGANES. No. 288,133. Patented Nolv. 6, 1883.

Eig. 5.

y UNITED STATES Afrnivi union,

VALVE-GEAR Foe STEAM-ENGINES.

SPECIFICATION forming part of Letters Patent No. 88,133, datedy November 6, 1883.

Application led February 24, 1883. (No model.)

d To all whom, t may concern,.-

\ ings.

My invention relates to improvements in operating valves of steam-engines. A

It consists in imparting to the valves an independent variable movement in connection or in combination with their general movements, whereby a differential instead of a regular movement and action of the valves upon their parts is obtained, the effect of which is to enable one valve to cut oft' at any required point and the other valve to retard the eX- haust until the stroke is completed.

The following description fully explains my improvement in operating engine-valves and the manner in which I proceed to construct and apply it, the accompanying drawings being referred to by iigures and letters-that is to say:

Figure 1 shows the application lto valvegear oi' a locomotive-engine. Figs. 2 and 3 are side and top views of mechanism by which thevariable movements of valves are obtained.

A represents a steam-cylinder B, its valvechamber; G G, the valves; d d e e, the supply and exhaustports, respectively, and E E the p piston and piston-rod.

Gr is valve-mechanism of well-known construction, operated by an eccentric. Connection between the valve mechanism Gr and valves is made by Suitable rods and an oscillating disk, l, which is suspended and moved back and `forth on a iixed point of oscillation, 2. llhe point of motion 2 is fixed in the end of a link, 3, to which the disk l is pivoted at 4, Fig. 1, so that it can turn also upon this point 4 as a center, in addition to its back-and-forward movement from center 2. A lever, 5,

forms anextension of said disk 1, is carried down and attached to the cross-head H of the piston-rod bya link, h. This lever is either By the reciprocations of the enginepiston a partially rotary movement ofthe disk backward andforward on its center 4 is obtained at the same time that the disk is being moved by the valve-gear in a longitudinal direction.

. Projecting from one face or side of the disk are two wrist-pins, 7 8, tov which are attached the outer ends of two valve-rods, 9 10, by means of links or connections 11 12. The wrist pins 7 and 8 are set upon the disk 1 at points between ninety and one hundred and eighty degrees apart, so as to give a differential movement to the valves, which cannot be obtained when the pins are opposite on the disk, as when in such position-i. e., opposite-one valve will be at one limit of throw and the other at the opposite limit.

Each valve has its own rod and a Separate connection with the disk 1. The front valve, C, is xed to the inner end of the rod 9, while the rod 10 extends into the valve-chamber beyond the first valve, and is connected to the rear valve, C.

-In the application of my invention shown in the drawings, the rod of the front valve is a hollow tube, and the second rod, 10, is carried through it to make direct connection with the rear valve. l do not coniine my improvement to this particular arrangement of valve-rods, however, as the attachment of the valves to the wrist-pins -7 and 8 by independent connections can be done in other ways that would be the equivalent of this construction. The valves G C being coupled in this manner by independent rods to the valvegear, they will reciprocate together and in the same general fresults from the rotary movement of the diskl 1 upon its center 4, and each valve, instead of 95 having a uniform rate of travel, has a variable movement. The degree of this variable movement is governed both by the distance ofthe wrist-pins from the center 4 of the disk and the length of the lever 5, and it can be in creased or diminished by the changing the position of the one or the length of the other in the construction.

Having thus fully described' my invention,

engine-piston, and then making connection of this disk by its center or aXis with the general valve -gear or valve-'actuating mechanism, whereby said valves receive independent movements from the rotation ofthe said disk,

which movements qualify and counteract the general movements received from the valvegear, substantially as described.

2. In valve-operating mechanism of steamengines, slide-valves, as C C', havingconnection with their valve-gear through the medium of separate valve-rods 9 10, and a disk, l, to which the rods are connected, said disk being provided with pins or connections 7 8, set

upon the said disk at points between ninety and one hundred and eighty degrees apart, substantially as and for the purpose herein 25 described.

3. In mechanism for operating valves of steam-engines, the disk l, having connection by points 7 8 with the valves by independent valve-rods 9 10, and suspended from a point 3o lof oscillation, 2, mechanism connecting said disk directly or indirectly with the enginepiston, to impart a rotary or a partially rotarymotion from the stroke of the piston, and the connecting-rod g, lby Which said disk receives 35 an oscillating movement from the valve-driving mechanism, substantially vas herein described, for the purpose set forth.

' ANDREW JACKSON STEVENS. Vtitnesses:

EDWARD E. OsBoRN, l F. M. DOWNEY. 

